The Germans call this position the Vielväter (many
fathers) position for the many authors who have constructed the literally
thousands of problems from this one position. For those who think chess is
played out, or that there are no new problems to composer, the development of
thousands of possibilities in stipulation from such a simple position should
show them to be very wrong. I'll give two classic examples so you can see how
it all started:

The Many
Fathers Position

RJ Darvall in the Fairy Chess Review of 1949 posed
the simple question here: Who wins? Whose move is it? That is for you to
find out and the most important part of the problem!

The answer is Black, as he has no last move. He
plays 1. ... axb6, and White must lose, as the pawn will queen and the white king
is one step behind! (Hide Solution)

Bror Larsson's addition here in feenschach 1981 was
to state: Retract one white move and mate in one. There is only one
answer! This one I definitely think you should try to solve. There is only one
move by White that could work and then allow a mate in one.

White retracts his last move 1. Kx(N)c8 and
instead plays 1. b7#. Why can't it just have been retract 1. Kc7-c8, without a
capture? Because then again Black would have no last move! If the piece were a
bishop, 1. b7 wouldn't be mate, and if the piece on c8 were a queen or rook,
white would have been in check, and unable to retract the capture and
mate. (Hide Solution)

Promotions

Promoting a piece to one that existed in the start
position is unique to chess. One can promote a checker piece to a king, but
that is a new piece that didn't exist before on the board. Chess is said to
have three such unique possibilities that other games lack - promotion, en
passant, and castling. Since each of those moves contains paradox, we will
explore them here, and begin with promotion.UnderpromotionWe'll start with a warm-up that should be fairly easy to
solve. But it was not easy to compose! As my young friend and promising study
composer Siegfried Hornecker noted on this one, "This was a day when the
heavens shone on a talented composer." White, despite his threatening pawns, is
also being threatened with mate. Only one way for White not to end up losing this
one. Enjoy!

1.d8N Re7 2.c8N Rd7 3.b8N Rc7 4.a8N Rxc8 5.Kxg7 Rf2 6.Nbc6 Kxa2 7.Nb6
draw! It is particularly nice as most problems of this type require constant
promotion to knight to check the black king. Here the promotions keep the white
king from being mated. (Hide Solution)

Allumwandlung

One of those dense German compound words, "Allumwandlung"
means "promotion to everything," thus a problem in which one side (or both, in
the case of a "gemischte" or "mixed set of promotions) promotes to every
possible piece during the course of the problem. It is usually abbreviated
"AUW" in all languages for ease of use.

In this Rex Solus problem (Black has only
a king), work out how two promotions on f8 and two on d8 lead to mate in 2 -
and only these four promotions to four different pieces lead to mate in two, no
other moves will do. 1. f8Q Kxd7 2. Qd5#;1. f8N+ Ke7 2. Qf6#; 1. d8R Ke7 2. Qf6#;1. d8B Kd7 2. Qd5#. (Hide Solution)

Another warm-up is this problem by Hanneman, this time
with conditions.

The first solution is easy to see: 1. e8Q#. As
would be expected, the weaker the piece, the longer to mate, so the key should
be easy; thus1. e8R+ Kd7 2. Re7#; 1.
e8B d5 2. Kc6 dxe 3. Bd7#, and 1. e8N Kd7 2. Ng7 (or c7, in a problem of this
sort, this dual is not as important as in a "regular" chess problem) d5 3. e5
d4 4. e6#. (Hide Solution)

Now follows the classic AUW problem. Now 105 plus years
old, the author indicated that it took him 12 years, in those pre-computer days,
to find a matrix that worked. In this case, I would consider that a dozen years
well-spent!

What is amazing about this one is that there are
no white captures required to carry out the AUW, only two duals (alternate
continuation) and only 12 total pieces are needed. Again, for the day, a
brilliant triumph for the human mind. I doubt, without a computer, that I could
compose something like this in 120 years, let alone twelve. The solution? 1.
f7! 1. ... e4 2. f8Q e3 3. Qe7/f6# ; 1. ... exd4 2. f8B Kf6 3. Ra6#; 1. ... exf4 2.
f8R Kd6 3. Rf6#; and finally 1. ... Kf6 2. f8N exd4 3. Rf7#. The first variation
contains the duals - White can promote to queen or rook, which may be why the
problem did not win an award (even then, problem judges could be pedantic!),
but note that the second variation shows what is called the Phoenix
theme, a white piece is removed from the board, but in the promotion, the exact
same piece (in this case, a bishop) reappears. (Hide Solution)

Matjaz Zigman was a talented problemist who died too
young. Here he showed a mixed AUW, a simple looking affair.

1.Qe1!and now:if 1. .. exf1R, then White ends the game with 2. Qxg3#if1. ... exf1B,
then white plays 2. Kxg3, and stalemates Black!If 1. .. exf1Q then 2. Kxg3 and black is forced to mate
white with 2. .. Qxe1#if 1. ...exf1N, then white plays 2. Qf2+! And whether
black captures with the King or the pawn, white has effected his own stalemate.Finally, there is the non thematic 1. ... g2, 2. Bxe2#.(Hide Solution)

En Passant

In a chess problem, en passant is used only when it can be
proved that the last move was the necessary "pawn fling" of two spaces. Here is
a nice simple example.

In the first part of this problem, it is fairly
easy to see that Black's last move had to have been g7-g5; with the WK on f5,
g6-g5 is not possible as the king would have been in check, so the solution is
1. hxg6#! (Hide Solution)

But the clever author didn't leave it as just that, he
added a "b" position to the mix, which is "move white bishop e5 to h8."

Here the author added a neat little piece of
retroanalytic content. In this position, with the WB on h8, Black has no last
move! But we still have a mate in one with black to move 1... g4 2. Bg7#!
(Hide Solution)

Castling

Again, Sam Loyd is the granddaddy of such problems, with
the following example.

All the white pieces are back where they started! The key,
even though it takes a flight from the Black king (g2) would be acceptable even
in a "normal" chess problem as it not only takes a flight, but gives one on h4,
a so-called "give and take" key.

Castling as a defensive strategy often involves partial
retro-analysis in order to determine if Black can castle. Often the trick is
that either the last move had to have been by the black king or rook. Can Black
castle in the following problem?

No! Black cannot castle here as he has to have
moved either the king or rook on his last move. Mate in eight may sound
difficult, but with so few pieces, think of it as endgame mating practice. What
move would you play over-the-board? 1.Qc1!, of course, to prevent the rook
check and start the process of cutting of the black king1. ... Kd8 2.Kd6 Ke8 3.Qc8+ Kf7 4.Qxh8 Kg6
5.Ke5 Kg5 6.Qg7 Kh4 7.Kf4 Kh3 8.Qg3# being one of the variations. (Hide Solution)

The answer is yes! Black's last move could have
been ... h6, so it is legal to castle on both sides. Thus, a key that would not
be considered acceptable in a "normal" chess problem is OK here since the idea
is to show both Black castlings:

That concludes our brief introduction to some of the
unusual chess problems out there; this just scratches the surface. If you want
more, consider either of these two books:

Addison, Stephen.Extraordinary
Chess Problems. Crowood Press, 1990.

Hochberg, Burt.Chess
Braintwisters. Sterling Publishing, 1999. One of the many good books from
the former editor of Chess Life.

The best book on unusual chess problems is actually Tim
Krabbé's Chess Curiosities, but is an incredibly hard book to find. Like
original copies of My 60 Memorable Games, used copies often sell for
several times the original price . There is also the Chess Problem Database
Server (PDB), at http://www.softdecc.com/pdb/index.pdb.
If you want to find problems by various stipulations such as Last Move? or
castling, go to http://www.softdecc.com/pdb/keywords.pdb?s=stip
to see the various possibilities.